Pumice stone



FIG. 1 is a top perspective view of a pumice stone in accordance with the present design.

FIG. 2 is a left side view of a pumice stone.

FIG. 3 is a top view of a pumice stone.

FIG. 4 is a right side view of a pumice stone.

FIG. 5 is a bottom view of a pumice stone.

FIG. 6 is a front view of a pumice stone; and,

FIG. 7 is a back view of a pumice stone.

The broken lines immediately adjacent the solid contour lines represent the bounds of the claim. The remaining broken lines illustrate portions of the pumice stone. None of the broken lines forms part of the claimed design. 

CLAIM The ornamental design for a pumice stone, as shown and described. 